Two-and-a-half weeks before the July 30 opening of the expanded Orange Line in Las Colinas, the Brookings Institution has released a new study that ranks North Texas among the worst regions in the country for connecting employers and employees by public transportation.

The research group’s study ranked the Dallas-Fort Worth-Arlington metropolitan area 81st out of 100 metropolitan areas in the country based on the percentage of jobs located near public transportation. The study found that roughly 58 percent of jobs in the area are located within three-quarters of a mile of public transportation.

That’s mostly in line with the rest of the state. The ranking is slightly worse than Austin-Round Rock and marginally better than Houston-Sugar Land-Baytown.

Broken down, the numbers show that 78.2 percent of jobs in the three major cities are near public transportation. Only 43.6 percent of jobs in the suburbs have transit access.

Much of the low ranking can be attributed to Arlington, which lacks public transportation, and the sprawl of North Texas suburbs, said Adie Tomer, the study’s author.

“The city of Dallas has very good transit — some of the best in the country, actually,” Tomer said. “The problem is we know that most people don’t live and work in Dallas. They either do one or the other.”

But a significantly lower percentage of workers are well-connected to their workplaces by public transit. The study found that less than 15 percent of jobs in North Texas are accessible within 90 minutes of all residents by public transportation. In that category, the Dallas area ranked 86th in the country.

Tomer said that’s a testament to the size of the metropolitan area alone. And the fact that the T in Fort Worth and DART are limited by their jurisdictions.

“If people want to move tens of miles away from the cities, the transit agencies can’t do much to service them,” Tomer said.

The expansion of the Orange Line to Las Colinas, a major business center, and the park-and-ride in northwest Plano are meant to help bridge that gap. Both will open July 30.

But access is just one piece of the problem for transit agencies. As Michael Lindenberger wrote about a month ago, DART’s challenge is to actually get people and companies on board.